Beholders have to be played with facing rules, due to the eyestalk combinations that can perform in a 90 degree arc. To be able to fire any ray it desires, the beholder must twist and turn in various combinations, which eat up precious movement and affect the ending placement of the central eye.
The eyestalk combinations for the gauth are:
Forward - Inflict Moderate Wounds & Exhaustion
Up - Scorching Ray & Exhaustion
Backward - Sleep & Dispel Magic
Down - Dispel Magic & Paralysis
Right - Sleep & Scorching Ray
Left - Paralysis & Exhaustion
Since the eye rays Goth wants to fire are on its left side, it needs to turn right, fire its rays, then turn back if it wants to face forward. Since the rays are free actions and Goth only used half of its movement (20 feet), this will not be a problem in this round. But Goth needs to be aware of the combinations in future rounds.